This quest is now harder to solo (as of Patch 2.0.7), through Stealth or Invisibility, due to the container no longer containing anything - it triggers an event which spawns an elite guardian which must be killed in order to obtain the fragment. The Guardian only drops the number of keys needed by the group. Upon leaving the instance, your copy of the key is deleted. This prevents you ungrouping and allowing others to join and loot the key. It should also be noted that if you spawn the Guardian Mob, and consequently wipe, then it is likely that you may not be able to loot the key fragment.

If you bring a party to obtain the key fragment and can defeat the Bog Overlords, getting to the key is a pretty quick process. Kill the two Bog Lords on the right side as you enter and skirt that edge. Following the Bog Lords, there is a pull of a 4-group of Naga, the 2-group at the front edge of the ramp (watch for the patrollers and pull them back) and then you can jump on to the "ramp" of rock-geometry just out of aggro range for the four group at the base of the ramp. Jump in the water and then get your key!

It is possible to get the fragment with 2 players and at least 2 [Invisibility Potion]s each. This method requires the first group to be pulled and a melee/spellcaster patrol to be pulled. After the two groups are dead, careful timing is required where each party member takes turns to run into the room and drink the potion the moment before they may pull aggro. Making the run seperately can prevent a full-party wipe. Once Invisible, run straight to the pond and aim for the second column to hide on the backside directly against it, away from the "ramp". When the potion wears off, you should be standing evenly between a large Naga group and two Mermidon guards next to the ramp. Wait for your 10 minute cooldown on the potions to wear off. Afterward, drink and proceed to the pond. Priests can use their Mind Vision spell to locate the "rest stop" and guide party members. Avoid Bog Overlords at all costs, as they are able to detect you while Invisible.

I hid the second fragment at the bottom of Serpent Lake, long before it was called that. The giant drain installed there after the naga took over has likely pulled the container into the depths of Coilfang Reservoir.

The third fragment will prove the most trying, as I left it inside Tempest Keep back when it was controlled by the naaru. Kael'thas now rules it and the chamber where I left it has become a prison.